Giro

This stop in the City of Westminster opens a door into professional road cycling. The world behind it is the Giro d'Italia, one of the three annual grand tours of the sport. The Tour de France and the Vuelta a España follow the same three-week format. Picture the start: around two hundred riders on the line, three weeks of racing ahead. Every racing day asks a little more than one hundred miles of them, usually covered in about four hours.

The route climbs mountains, crosses long flat stretches and runs through every kind of weather. Riders travel packed into huge groups, where a single mistake can bring a whole bunch down at about twenty-five miles per hour. The rules carry a hard edge: finish more than about half an hour behind the first rider home, and you go home. Selection alone marks you as one of the best road cyclists in the world, and finishing is an achievement in itself. Teams of eight serve a single leader, while a team car follows with advice, data, repairs and water bottles. Much of the tactics turns on air resistance, with riders taking shelter in each other's slipstream. Every day is a race in itself, and the first rider over the line wins the stage. The overall victory rests on the general classification, a running total of every rider's time. Points also reward the best sprinters and the fastest climbers, and a daily prize goes to the most aggressive riding. Some riders chase none of it, spending all three weeks helping their leader win instead.

Behind the racing, a support crew manages nutrition, hydration and sleep, keeping every rider in top condition. Even on the two rest days, the riders stay in the saddle with a light spin to keep their legs in shape.